1. Field of the Invention
The present invention pertains to control apparatus intended for alternating-current motor use; it relates more specifically to control apparatus capable of driving alternating-current motors different in type.
2. Prior Art
Alternating-current motors (hereinafter, referred to as AC motors) are divided into a plurality of types, including an induction type and a synchronous type, according to the particular principles of torque generation. Conventional control apparatus for driving AC motors consists of several units each having the appropriate control scheme according to the particular type of AC motor and each unit is used according to the type of AC motor to be driven. For example, as described in Japanese Application Patent Laid-Open Publication No. Hei 6-265607, when an induction motor (hereinafter, referred to as IM) is to be driven, auto-tuning with an IM driving inverter is provided to measure motor constants automatically for improved torque performance prior to the start of operation. Also, only IM is controlled by a unit generally called the general-purpose inverter, which has versatility with respect to the motor constants of IM.
Among inverter units of the vector control type is a unit constructed so that as disclosed in Patent Official Gazette Issue No. 2708479, the unit can drive an induction motor and asynchronous motor. For this type of unit, however, the types of motors to be driven need to be specified beforehand.
Recently, new types of motors such as an inserted permanent magnet-type motor (hereinafter, referred to as IPM), a surface-attached permanent magnet-type motor (likewise, referred to as SPM), and a synchronous reluctance motor (likewise, referred to as SynRM), have been developed and commercialized as motors other than IM. Control apparatus for driving and controlling these new motors has also been developed. To drive each such motor, however, it has been necessary to use special control apparatus for each.
An object of the present invention is to supply the method and AC motor control apparatus that enable automatic identification of the types of not only IM but also other AC motors (such as IPM, SPM, and SynRM) that are connected to the apparatus, even if the user does not understand the types of motors. Another object of the present invention is to supply equipment that automatically selects the appropriate motor control schemes for each motor type which has been identified using the above-mentioned method, and drives each motor by using the motor constants that have been obtained during motor type identification, as the settings of the motor constants for conducting variable-speed control of the motor mentioned above.
The AC motor control apparatus pertaining to the present invention has a motor type identification means by which the type of motor connected to the motor control apparatus is identified by issuing the appropriate voltage command for motor type identification and judging from the detected current whether the motor rotor is equipped with a magnet and has magnetic salience. The AC motor control apparatus pertaining to the present invention also has a control scheme selection means which selects the appropriate control scheme according to the above-identified type of motor and controls the driving of the motor.